Method for preparing chlorohydrins composition and method for preparing epichlorohydrin using chlorohydrins composition prepared thereby

ABSTRACT

A method of preparing a chlorohydrin composition and a method of preparing epichlorohydrin by using a chlorohydrin composition prepared by using the method are provided. The method of preparing a chlorohydrin composition in which a polyhydroxy aliphatic hydrocarbon is reacted with a chlorination agent in the presence of a catalyst includes performing at least one combination of a series of unit operations comprising a first reaction step, a water removal step, and a second reaction step in this stated order, wherein the method further includes mixing a chlorohydrin concentrate obtained by purifying the reaction mixture discharged from the final reaction step from among the plurality of reaction steps and a water-rich layer discharged from the water-removal step. The method of preparing epichlorohydrin includes contacting the chlorohydrin composition prepared by using the method of preparing a chlorohydrin composition with an alkaline agent.

TECHNICAL FIELD

The present invention relates to a method of preparing a chlorohydrincomposition and a method of preparing epichlorohydrin by using achlorohydrin composition prepared by using the method. In particular,the present invention relates to a method of preparing a chlorohydrincomposition in which in the presence of a catalyst, a polyhydroxyaliphatic hydrocarbon is reacted with a chlorination agent, the methodincluding at least one combination of a series of unit operationsincluding: a first reaction step, a water removal step, and a secondreaction step in this stated order, wherein the method further includesmixing a chlorohydrin concentrate obtained by purifying the reactionmixture discharged from the final reaction step from among the pluralityof reaction steps and a water-rich layer discharged from thewater-removal step, and to a method of preparing epichlorohydrin bycontacting a chlorohydrin composition prepared by using the method withan alkaline agent.

BACKGROUND ART

Currently, bio-diesel is competitively developed worldwide and produced,and even in Korea, the production of bio-diesel has been already begunand bio-diesel is commercially available as an additive of diesel oil.

In the procedure of producing bio-diesel, a great quantity of glycerolcorresponding to about 10% of the production amount of the bio-diesel isproduced. However, glycerol is excessively supplied in view of thedemand thereof, and thus, the value of glycerol continuously decreases.Accordingly, there is a need to increase added-value of glycerol byconverting glycerol into chlorohydrins, such as dichloropropanol.

Meanwhile, chlorohydrins, such as dichloropropanol, are used as a rawmaterial for preparing epichlorohydrin, and the most of commerciallyavailable chlorohydrins are prepared from propylene. In particular, amethod of preparing a chlorohydrin composition includes preparing allylchloride by high-temperature chlorination reaction of propylene andreacting the allyl chloride with a chlorination agent by using excessindustrial water to prepare chlorohydrins. However, the method ofpreparing a chlorohydrin composition using propylene has many problemsincluding an unstable supply of propylene due to its price increase,generation of great quantities of waste water and waste matter, andexcessive initial investment costs due to the two-step method andresulting difficulty in newly constructing/modifying of manufacturingapparatuses.

Accordingly, a one-step method of directly preparing a chlorohydrincomposition including reacting a polyhydroxy aliphatic hydrocarbon, suchas glycerol, which is a by-product of bio-diesel, with a chlorinationagent in the presence of a catalyst is economical. The one-step methodof preparing chlorohydrins by using a polyhydroxy aliphatic hydrocarbon,such as glycerol, as reaction raw materials may have lower manufacturingcosts due to the use of a cheap polyhydroxy aliphatic hydrocarbon. Inaddition, during the preparation process, industrial water is not used,and thus, generation of waste water and waste matter may bepredominantly reduced, thereby being environmentally friendly.Furthermore, the one-step method may contribute to a decrease in processand environment-related investment costs, leading to a lower initialinvestment costs.

However, the method of preparing a chlorohydrin composition produceswater as a by-product and the generated water inhibits a chlorinationreaction of the polyhydroxy aliphatic hydrocarbon, such as glycerol, sothat as the reaction progresses, the reaction rate gradually decreases,the reaction time increases, and selectivity of chlorohydrins decreases.

DETAILED DESCRIPTION OF THE INVENTION Technical Problem

An embodiment of the present invention provides a method of preparing achlorohydrins composition in which in the presence of a catalyst, apolyhydroxy aliphatic hydrocarbon is reacted with a chlorination agent,the method including at least one combination of a series of unitoperations including: a first reaction step, a water removal step, and asecond reaction step in this stated order, wherein the method furtherincludes mixing a chlorohydrin concentrate obtained by purifying thereaction mixture discharged from the final reaction step from among theplurality of reaction steps and a water-rich layer discharged from thewater-removal step, and a method of preparing epichlorohydrin byreacting a chlorohydrin composition prepared by using the method with analkaline agent.

Another embodiment of the present invention provides a method ofpreparing epichlorohydrin, wherein the method includes contacting achlorohydrin composition prepared by using the method of preparing achlorohydrin composition with an alkaline agent.

Technical Solution

According to an aspect of the invention, a method of preparing achlorohydrin composition in which a polyhydroxy aliphatic hydrocarbon isreacted with a chlorination agent in the presence of a catalyst,includes: at least one combination of a series of unit operationsincluding a first reaction step for reacting the polyhydroxy aliphatichydrocarbon with the chlorination agent; a water removal step forseparating a reaction mixture including water as a by-product dischargedfrom the first reaction step into a water-rich layer and awater-deficient layer; and a second reaction step for reacting at leastone constituent of the reaction mixture from which water is removed,with at least one of the chlorination agent and an additionalchlorination agent, wherein these steps are performed in this statedorder, and the method further includes purifying the reaction mixturedischarged from the final reaction step from among the plurarity ofreaction steps to obtain a chlorohydrin concentrate, and mixing thewater-rich layer, and the chlorohydrin concentrate.

According to another aspect of the invention, a method of preparing achlorohydrin composition includes: introducing a polyhydroxy aliphatichydrocarbon, a catalyst, and a chlorination agent into a first reactorin which the temperature is maintained in a range of 50 to 200° C.;discharging a first reactor effluent including water as a by-productfrom the first reactor; introducing at least a portion of the firstreactor effluent into a water removal device to separate it into awater-rich layer and a water-deficient layer; introducing thewater-deficient layer and an additional chlorination agent into a secondreactor in which the temperature is maintained in a range of 80 to 200°C.; introducing at least a portion of a second reactor effluent into apurification device for chlorohydrins to obtain a chlorohydrinsconcentrate; and mixing the water-rich layer and the chlorohydrinconcentrate.

The polyhydroxy aliphatic hydrocarbon may be a C₂ to C₂₀ compound thatcontains two or more hydroxyl groups bonded to different carbon atoms.

The polyhydroxy aliphatic hydrocarbon may include at least one compoundselected from the group consisting of 1,2-ethanediol, 1,2-propanediol,1,3-propanediol, 3-chloro-1,2-propanediol, 2-chloro-1,3-propanediol,glycerol, 1,2,4-butanetriol, 1,4-butanediol, and esters of thesecompounds.

The chlorohydrins included in the chlorohydrin concentrate may be acompound including at least one hydroxyl group and at least one chlorineatom that are bonded to different carbon atoms.

The chlorohydrins may include at least one type of compound selectedfrom the group consisting of 3-chloro-1,2-propanediol,2-chloro-1,3-propanediol, 1,3-dichloropropane-2-ol, and2,3-dichloropropane-1-ol.

The catalyst may include at least one selected from the group consistingof an organic acid catalyst, a carboxylic acid-based catalyst, anitrile-based catalyst, and a solid catalyst.

In the first reactor, a reaction product of the catalyst and thepolyhydroxy aliphatic hydrocarbon may be formed as an intermediateproduct, and the intermediate product may act as a catalyst in achlorination reaction of the polyhydroxy aliphatic hydrocarbon.

The polyhydroxy aliphatic hydrocarbon may include glycerol, the catalystmay include an acetic acid, and the intermediate product may includeglycerol acetates.

The chlorination agent may include a hydrogen chloride gas or an aqueoushydrochloric acid solution.

The first reactor effluent introduced into the water removal device maybe discharged when a conversion rate of the polyhydroxy aliphatichydrocarbon is in a range of 30 to 100% and the yield of thechlorohydrins is in a range of 30 to 95%, in the first reactor.

The first reactor effluent introduced into the water removal device mayinclude the polyhydroxy aliphatic hydrocarbon, the chlorohydrins, andthe intermediate product at a ratio of 0 to 90 parts by weight of thepolyhydroxy aliphatic hydrocarbon: 5 to 95 parts by weight of thechlorohydrins: 5 to 12 parts by weight of the intermediate product.

The first reactor effluent introduced into the water removal device mayinclude the chlorination agent and water at a ratio of 10 to 25 parts byweight of the total of the chlorination agent and the additionalchlorination agent and 75 to 90 parts by weight of water.

A chlorination agent may be additionally introduced into the secondreactor.

A retention time of the reactor may content in the first reactor is in arange of 20 minutes to 1 hour, and a retention time of the reactorcontents in the second reactor may be in a range of 1 to 3 hours.

The water removal device may be operated by distillation operation usinga boiling point difference between constituents of the first reactoreffluent.

The first reactor and the second reactor may be maintained at anatmospheric pressure or higher, and the water removal device may bemaintained at an atmospheric pressure or lower.

The first reactor and the second reactor may be maintained at 1 to 20atm, and the water removal device may be maintained at 10 to 760 mmHg.

The water removal device may include a vacuum distillation column havinga to theoretical plate number of 2 to 50.

The first reactor effluent may be introduced into the water removaldevice after being decompressed in a decompression device.

The decompression device may include a decompression valve.

The first reactor and the second reactor may be each independently acontinuous stirred-tank reactor, a batch reactor, a semi-batch reactor,or a plug flow reactor.

The second reactor effluent may include 0 to 10 parts by weight of thepolyhydroxy aliphatic hydrocarbon, 80 to 98 parts by weight of thechlorohydrins, 0 to 10 parts by weight of the total of the chlorinationagent and the additional chlorination agent, and 1 to 20 parts by weightof water.

The chlorohydrin composition may include 0 to 10 parts by weight of thepolyhydroxy aliphatic hydrocarbon, 60 to 96 parts by weight of thechlorohydrins, 0 to 20 parts by weight of the total of the chlorinationagent and the additional chlorination agent, and 0 to 30 parts by weightof water.

According to another aspect of the invention, a method of preparingepichlorohydrin includes diluting the chlorohydrin composition preparedby using the method of claim 1 or claim 2 with water, followed bycontacting the diluted chlorohydrin composition with an alkaline agentat a temperature of 20 to 100° C., wherein the diluted chlorohydrincomposition includes 0 to 5 parts by weight of the polyhydroxy aliphatichydrocarbon, 10 to 40 parts by weight of the chlorohydrins, 0 to 5 partsby weight of the total of the chlorination agent and the additionalchlorination agent, and 50 to 90 parts by weight of water.

The diluted chlorohydrin composition additionally may include acatalyst, and the catalyst may react with the alkaline agent to form analkali metal salt.

Advantageous Effects

According to an embodiment of the present invention, there is provided amethod of preparing a chlorohydrin composition with improved selectivityof chlorohydrins.

According to another aspect of the present invention, there is provideda method of preparing epichlorohydrin, wherein the method includescontacting a chlorohydrin composition prepared by using the method ofpreparing a chlorohydrin composition with an alkaline agent.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating a method of preparing a chlorohydrincomposition according to an embodiment of the present invention and amethod of preparing epichlorohydrin using the prepared chlorohydrincomposition.

BEST MODE

Hereinafter, a method of preparing a chlorohydrin composition and amethod of preparing epichlorohydrin, according to embodiments of thepresent invention, are described in detail.

The method of preparing a chlorohydrin composition, according to thepresent embodiment, includes reacting a polyhydroxy aliphatichydrocarbon with a chlorination agent in the presence of a catalyst.

The method of preparing a chlorohydrin composition includes at least onecombination of a series of unit operations including: a first reactionstep for reacting a polyhydroxy aliphatic hydrocarbon with achlorination agent, a water removal step for separating a reactionmixture including water as a by-product discharged from the firstreaction step into a water-rich layer and a water-deficient layer, and asecond reaction step for reacting at least one constituent of thedehydrated reaction mixture with at least one of the chlorination agentand an additional chlorination agent. A chlorination agent may not beadditionally added to the water removal step.

In addition, the method of preparing a chlorohydrin composition furtherincludes purifying the reaction mixture discharged from the finalreaction step from among the plurality of reaction steps to obtain achlorohydrin concentrate, and mixing the water-rich layer and thechlorohydrin concentrate.

Hereinafter, the method of preparing chlorohydrins will be described indetail with reference to FIG. 1.

In this specification, ‘chlorohydrins’ refers to chlorohydrins, estersof chlorohydrins, or a mixture thereof.

The chlorohydrins may be a compound having at least one hydroxyl groupand at least one chlorine atom which are bonded to different carbonatoms. For example, the chlorohydrins may include at least one compoundselected from the group consisting of 3-chloro-1,2-propanediol,2-chloro-1,3-propanediol, 1,3-dichloropropane-2-ol, and2,3-dichloropropane-1-ol. In the present specification,3-chloro-1,2-propanediol and 2-chloro-1,3-propanediol are collectivelyreferred to as “monochloropropanediol,” and 1,3-dichloropropane-2-ol and2,3-dichloropropane-1-ol are collectively referred to as“dichloropropaneol.”

In the method of preparing a chlorohydrins according to an embodiment ofthe present invention, 1,3-dichloropropane-2-ol is predominantlyproduced, and particularly, suitable for use as a reaction raw materialto prepare epichlorohydrin.

Referring to FIG. 1, a polyhydroxy aliphatic hydrocarbon and a catalystare introduced into a first reactor 110 via a line 1. In addition, achlorination agent is introduced into the first reactor 110 via a line 2and/or other paths.

The polyhydroxy aliphatic hydrocarbon may be a C₂-C₂₀ compound having atleast two hydroxyl groups bonded to different carbon atoms. Thepolyhydroxy aliphatic hydrocarbon may include at least one compoundselected from the group consisting of 1,2-ethanediol, 1,2-propanediol,1,3-propanediol, 3-chloro-1,2-propanediol, 2-chloro-1,3-propanediol,glycerol, 1,2,4-butanetriol, 1,4-butanediol, and esters of thesecompounds.

The catalyst may be an organic acid catalyst, a carboxylic acid-basedcatalyst, a nitrile-based catalyst, a solid catalyst, or a mixture of atleast two of these catalysts.

The organic acid catalyst may include, for example, at least onecompound selected from the group consisting of a monocarboxylic acid, adicarboxylic acid, a polycarboxylic acid, a malonic acid, a levulinicacid, a citric acid, a succinic acid, a propionic acid, and derivativesof these organic acids.

The carboxylic acid-based catalyst may include, for example, at leastone compound selected from the group consisting of monocarboxylic acidester, polycarboxylic acid ester, monocarboxylic acid anhydrides,polycarboxylic acid anhydrides, monocarboxylic acid chlorides,polycarboxylic acid chlorides, monocarboxylic acid salts, polycarboxylicacid salts, and derivatives of these carboxylic acid based compounds.

The nitrile-based catalyst may include, for example, at least onecompound selected from the group consisting of acetonitrile,propionitrile, acrylonitrile, valeronitrile, isobutyronitrile,hydroxyacetonitrile, chloroacetonitrile, succinonitrile, glutaronitrile,adiponitrile, and phenylacetonitrile.

The solid catalyst may include, for example, at least one compoundselected from the group consisting of an inorganic oxide, an inorganichalide, a strong-acidic organic compound, and mixtures of at least twoof these.

The inorganic oxide may include at least one compound selected from thegroup consisting of metal oxide, composite oxide, oxy acid, and oxy acidsalt. The metal oxide may be, for example, SiO₂, Al₂O₃, TiO₂, Fe₂O₃,ZrO₂, SnO₂, CeO₂, Ga₂O₃, or La₂O₃. The composite oxide may be, forexample, SiO₂—Al₂O₃, SiO₂—TiO₂, TiO₂—ZrO₂, SiO₂—ZrO₂, MoO₃—ZrO₂,zeolite, a heteropoly acid (i.e., a poly acid including P, Mo, V, W, Sior the like), or a heteropoly acid salt. Examples of the oxy acid andoxy acid salt include BPO₄, AlPO₄, poly phosphoric acid, acidicphosphate, H₃BO₃, acidic borate, and niobic acid.

The inorganic halide may be a metal halide such as a metal fluoride, ametal chloride, a metal bromide, or a metal iodide of a Group 3A elementsuch as scandium, yttrium, lanthanum, or actinium; a Group 4A elementsuch as titanium, zirconium, or hafnium; a Group 5A element such asvanadium, niobium, or tantalum; a Group 8 element such as iron, cobalt,nickel, palladium, or platinum; a Group 2B element such as zinc; a Group3B element such as aluminum or gallium; or a Group 4B element such asgermanium or tin.

The strong acidic organic compound may be, for example, an organicsulfonic acid compound such as a sulfonate group-containing ion-exchangeresin or a condensed carbon ring-containing sulfonic acid compound.

The amount of the catalyst introduced may be from 1 to 10 parts byweight based on 100 parts by weight of the polyhydroxy aliphatichydrocarbon. When the amount of the catalyst introduced is within thisrange, a reaction rate may be satisfactorily improved with anappropriate amount of the catalyst.

In the method of preparing a chlorohydrin composition, the first reactor110 may be maintained at a temperature from 50 to 200° C. When thetemperature of the first reactor 110 is within this range, a highreaction rate may be obtained by the application of an appropriate levelof energy. In addition, the first reactor 110 may be maintained at anatmospheric pressure or higher, for example, at 1 to 20 atm. When thepressure of the first reactor 110 is within this range, relatively highreaction activity may be obtained. In this case, even when the pressureof the first reactor 110 is greater than 20 atm, an effect of anincrease in reaction activity according to the increase in pressure isnot significant. In addition, the first reactor 110 may be a continuousstirred tank reactor (CSTR), but is not limited thereto. For example,the first reactor 110 may be a batch reactor, a semi-batch reactor, or aplug flow reactor. In the first reactor 110, in addition tochlorohydrins as a main product, a reaction product of the catalyst andthe polyhydroxy aliphatic hydrocarbon as an intermediate product isproduced. The intermediate product may act as a catalyst in thechlorination of the polyhydroxy aliphatic hydrocarbon (e.g., a reactionfor producing chlorohydrins which occurs in the first reactor 110 and/ora second reactor 150.) For example, when the polyhydroxy aliphatichydrocarbon includes glycerol and the catalyst includes acetic acid, theintermediate product may include glycerol acetates. As used herein, theterm “glycerol acetates” indicates a substituted or unsubstitutedglycerol monoacetate, a substituted or unsubstituted glycerol diacetate,a substituted or unsubstituted glycerol triacetate, or a mixture ofthese compounds. In addition, the term “substituted” as used hereinmeans that a hydrogen atom of a compound is substituted with a halogengroup, a hydroxyl group, an alkyl group, an alkoxy group, an aminegroup, or a combination thereof. In addition, a retention time of thereactor contents in the first reactor 110 may be from 20 minutes to 1hour. When the retention time of the reactor contents in the firstreactor 110 is within this range, a high conversion rate of thepolyhydroxy aliphatic hydrocarbon may be obtained within an appropriateperiod of time.

The chlorination agent may include a hydrogen chloride gas or an aqueoushydrochloric acid solution.

An example of the reaction occurring in the first reactor 110 is thechlorination reaction of the polyhydroxy aliphatic hydrocarbon (e.g.,glycerol) which is represented by Reaction Scheme 1 below:

In the above reaction, the conversion rate of glycerol, the yield ofmonochloropropanediol (MCP), the yield of dichloropropanol (DCP), theselectivity of monochloropropanediol (MCP), and the selectivity of DCPmay be calculated respectively by Equations 1 through 5 below:Conversion rate of glycerol (%)=(number of moles of glycerolreacted)/(number of moles of glycerol introduced)×100;   [Equation 1]Yield of MCP (%)=(number of moles of monochloropropanediolgenerated)/(number of moles of glycerol introduced)×100;   [Equation 2]Yield of DCP (%)=(number of moles of DCP generated)/(number of moles ofglycerol introduced)×100;   [Equation 3]Selectivity of monochloropropanediol (MCP)=(number of moles of MCPgenerated)/(total number of moles of reaction products)×100; and  [Equation 4]Selectivity of dichloropropanol (DCP)=(number of moles of DCPgenerated)/(total number of moles of reaction products)×100.   [Equation5]

After the retention time elapses, a first reactor effluent is dischargedfrom the first reactor 110 and flows into a line 3 and/or a line 4. Thatis, at least a portion of the first reactor effluent flows into a firstmixing device 120 via the line 3, and the remaining portion of the firstreactor effluent is decompressed in a decompression device 131 and thenflows into a water removal device 140 via the line 4. Herein, the firstreactor effluent may include a catalyst; chlorohydrins; an intermediateproduct such as glycerol acetates; water; an unreacted polyhydroxyaliphatic hydrocarbon; and/or a chlorination agent. In addition, thechlorination agent is introduced into the first mixing device 120 viathe line 2. In the first mixing device 120, the first reactor effluentis mixed with the chlorination agent and then recycled to the firstreactor 110.

The first mixing device 120 may include an ejector, an inline mixer, anultrasonic mixture, or a mixture of at least two of these. When anejector is used as the first mixing device 120, the first reactoreffluent may act as a motive fluid and the chlorination agent may act asa suction fluid.

The decompression device 131 may include a decompression valve.

The additional chlorination agent may include a hydrogen chloride gas oran to aqueous hydrochloric acid solution.

The water removal device 140 may be operated by distillation operationbased on a boiling point difference between constituents of the firstreactor effluent.

In addition, the water removal device 140 may be maintained at anatmospheric pressure or lower, for example, at 10 to 760 mmHg. When thepressure of the water removal device 140 is within this range, atemperature of a downstream effluent (i.e., water-deficient layer) isappropriate, and thus, an amount of high boiling point materialgenerated is decreased and clogging of the water removal device 140 andpipelines may be prevented. The water removal device 140 may include avacuum distillation column having a theoretical plate number of 2 to 50(i.e., a dehydration column 141). When the theoretical plate number ofthe vacuum distillation column is within this range, the amount ofmoisture remaining in the water-deficient layer may be minimized. Asused herein, the term “theoretical plate number” indicates the number ofimaginary regions or plates where two phases, such as gas and liquidphases, reach equilibrium, in a separation process using the vacuumdistillation column.

The first reactor effluent introduced into the water removal device 140may be discharged when the conversion rate of the polyhydroxy aliphatichydrocarbon is in a range of 30 to 100% and the yield of thechlorohydrins is in a range of 30 to 95%, in the first reactor 110. Inthe first reactor effluent introduced into the water removal device 140,when the conversion rate of the polyhydroxy aliphatic hydrocarbon andthe yield of the chlorohydrins are within the ranges described above, adecrease in a reaction rate in the first reactor 110 does not occur andthe water removal device 140 may have high water removal effects. Inaddition, a high selectivity of chlorohydrins in the first reactor 110may be obtained. For example, the first reactor effluent introduced intothe water removal device 140 may include 0 to 90 parts by weight of thepolyhydroxy aliphatic hydrocarbon, 5 to 95 parts by weight of thechlorohydrin, and 5 to 12 parts by weight of the intermediate product(e.g., glycerol acetates).

In addition, the first reactor effluent introduced into the waterremoval device 140 may include 10 to 25 parts by weight of the total ofthe chlorination agent and the additional chlorination agent and 75 to90 parts by weight of water. When the amounts of the chlorination agentand the water are within the ranges described above, the first reactoreffluent may form an azeotropic mixture, and thus, the solubility of thechlorination agent with respect to the water increases so that a loss ofthe chlorination agent may be minimized.

The first reactor effluent introduced into the water removal device 140via the line 4 is separated into a gas phase material and othermaterials (i.e., a liquid phase material and a solid phase material) ina dehydration column 141. Thereafter, the gas phase material iscondensed in a condenser 143 and flows into a line 5, and the othermaterials are distilled in a reboiler 142 and separated again into a gasphase material and other materials. Afterwards, the gas phase materialis recycled to the dehydration column 141 and the other materials flowinto the second reactor 150 via a line 6. In particular, a material(hereinafter, referred to as “water-rich layer”) that is condensed inthe condenser 143 and flows into the line 5 after being discharged froman upper portion of the dehydration column 141 may include water and achlorination agent, and a material (hereinafter, referred to as“water-deficient layer”) that does not vaporize in the reboiler 142 andflows into the line 6 after being discharged from a lower portion of thedehydration column 141 may include an unreacted polyhydroxy aliphatichydrocarbon, chlorohydrins, and/or the above-described intermediateproduct. The intermediate product is introduced into the second reactor150 and acts as a catalyst for the chlorination reaction of ReactionScheme 1, and thus, the reaction may smoothly occur in the secondreactor 150 without further adding a catalyst.

The reboiler 142 and the condenser 143 may be maintained at 100 to 200°C. and 0 to 60° C., respectively.

The second reactor 150 may be maintained at 70 to 200° C. When thetemperature of the second reactor 150 is within the range describedabove, chlorohydrins may be obtained with a high yield by theapplication of an appropriate level of energy. In addition, the secondreactor 150 may be maintained at an atmospheric pressure or higher, forexample, 1 to 20 atm. When the pressure of the second reactor 150 iswithin this range, the solubility of the chlorination agent with respectto the contents of the second reactor 150 may be improved. The secondreactor 150 may be a CSTR, but is not limited thereto. For example, thesecond reactor 150 may be a batch reactor, a semi-batch reactor, or aplug flow reactor. In the second reactor 150, chlorohydrins areadditionally generated by contacting the above-described intermediateproduct with an additional chlorination agent that is separately addedto the second reactor 150. The retention time of the reactor contents inthe second reactor 150 may be from 1 to 3 hours. When the retention timeof the second reactor contents is within this range, chlorohydrins maybe obtained with a high yield within an appropriate period of time.

The reaction that occurs in the second reactor 150 is the same as orsimilar to that occurring in the first reactor 110.

After the retention time elapses, a second reactor effluent isdischarged from the second reactor 150 and introduced into a line 7and/or a line 9. That is, at least a portion of the second reactoreffluent is introduced into a second mixing device 160 via is the line7, and the remaining portion of the second reactor effluent isdecompressed in a second decompression device 132, and then, introducedinto a first distillation device 170 via a line 9. In this regard, thesecond reactor effluent may include a catalyst; chlorohydrins; anintermediate product such as glycerol acetates; water; an unreactedpolyhydroxy aliphatic hydrocarbon; and/or a chlorination agent. Theadditional chlorination agent is introduced into the second mixingdevice 160 via a line 8. In the second mixing device 160, the secondreactor effluent is mixed with the additional chlorination agent, andthe resulting mixture is then recycled to the second reactor 150. Theadditional chlorination agent may be introduced into the second reactor150 via other paths, in addition to the line 8.

The second mixing device 160 may include an ejector, an inline mixer, anultrasonic mixture, or a mixture of at least two of these. When anejector is used as the second mixing device 160, the second reactoreffluent may act as a motive fluid and the additional chlorination agentmay act as a suction fluid.

The second decompression device 132 may include a decompression valve.

The first distillation device 170 may be operated by distillationoperation based on a boiling point difference between constituents ofthe second reactor effluent.

In addition, the first distillation device 170 may be maintained at anatmospheric pressure or lower, for example, 10 to 760 mmHg. When thepressure of the first distillation device 170 is within the rangedescribed above, chlorohydrins may be separated with a high efficiency.The first distillation device 170 may include a vacuum distillationcolumn having a theoretical plate number of 2 to 50 (i.e., a separationcolumn 171). When the theoretical plate number of the vacuumdistillation column is within this range, chlorohydrins may be separatedwith a high efficiency.

The second reactor effluent introduced into the first distillationdevice 170 may include 0 to 10 parts by weight of the polyhydroxyaliphatic hydrocarbon, 80 to 98 parts by weight of the chlorohydrins, 0to 10 parts by weight of the total of the chlorination agent and theadditional chlorination agent, and 1 to 20 parts by weight of water.When the amounts of the constituents of the second reactor effluent arewithin the range described above, the reaction is completed and thus theyield of the chlorohydrins is maximized.

The second reactor effluent that is introduced into the firstdistillation device 170 via the line 9 is separated into a gas phasematerial and a liquid phase material in the separation column 171.Thereafter, the gas phase material is condensed in a second condenser173 and flows into a line 10, and the liquid phase material is distilledin a second reboiler 172 and separated again into a gas phase materialand a liquid phase material. Afterwards, the gas phase material isrecycled to the separation column 171 and the liquid phase material isintroduced into a stripping device 180 via a line 11. In particular, amaterial that is condensed in the second condenser 173 and flows intothe line 10 after being discharged from an upper portion of theseparation column 171 may include chlorohydrins, water and/or achlorination agent, and a high boiling point material that does notvaporize in the second reboiler 172 and flows into the line 11 afterbeing discharged from a lower portion of the separation column 171 mayinclude an intermediate product, such as glycerol acetates. In thisregard, a considerable amount of chlorohydrins may flow into the line 11together with the intermediate product. Herein, the second reboiler 172and the second condenser 173 may be maintained at a temperature of 100to 200° C. and 0 to 60° C., respectively.

In the first distillation device 170, a chlorination reaction of thepolyhydroxy aliphatic hydrocarbon, i.e., a reaction for generatingchlorohydrins, may further occur.

The stripping device 180 separates a low boiling point material such aschlorohydrins that is introduced together with the high boiling pointmaterial via the line 11 by using steam that is supplied via a line 12.The low boiling point material that is collected by the stripping device180 flows into a line 13, and the high boiling point material isdischarged to the outside via a line 14.

The first distillation device 170 and the stripping device 180 arecollectively referred to as a chlorohydrins refiner.

The materials that are introduced into the lines 10 and 13 arecollectively referred to as a concentrate of chlorohydrins (hereinafterreferred to as “a chlorohydrin concentrate”).

The materials that are introduced into the lines 5, 10 and 13 may becombined together at a single location to form a first composition ofchlorohydrins.

The first composition of chlorohydrins may include 0 to 10 parts byweight of the polyhydroxy aliphatic hydrocarbon, 60 to 96 parts byweight of the chlorohydrins, 0 to 20 parts by weight of the total of thechlorination agent and the additional chlorination agent, and 0 to 30parts by weight of water.

When the method of preparing a chlorohydrin composition as describedabove is used, water, which is a by-product, is removed without loss ofthe chlorination agent and/or the catalyst, and thus, a reduction inreaction rate may be prevented and the selectivity of chlorohydrins maybe increased.

The first composition of chlorohydrins may be used to prepareepichlorohydrin. In this regard, the first composition of chlorohydrinsmay be diluted with water before being used to prepare epichlorohydrinto form a second composition of chlorohydrins. In particular, referringto FIG. 1, the first composition of chlorohydrins introduced via a line15 may be mixed with water introduced via a line 16 to form a secondcomposition of chlorohydrins. This is because when epichlorohydrin isprepared using a high concentration of chlorohydrins, the amount ofby-products produced increases and thus the selectivity of theepichlorohydrin is decreased. In the diluting process, the amount of thewater added may be from 100 to 500 parts by weight based on 100 parts byweight of the first composition of chlorohydrins. When the amount of thewater added is within this range, the amount of by-products may bereduced by an appropriate amount of water, and thus, the yield of theepichlorohydrin may be maximized.

The second composition of chlorohydrins may be used as a reactant forthe preparation of epichlorohydrin along with an alkaline agent. Thesecond composition of chlorohydrins may include 0 to 5 parts by weightof the polyhydroxy aliphatic hydrocarbon, 10 to 40 parts by weight ofthe chlorohydrins, 0 to 5 parts by weight of the total of thechlorination agent and the additional chlorination agent, and 50 to 90parts by weight of water.

When the amounts of constituents of the second composition ofchlorohydrins are within the ranges described above, the amounts ofby-products decreases, and thus, the yield of the epichlorohydrin may bemaximized.

In an inline reactor 190, the second composition of chlorohydrins maycontact an alkaline agent (e.g., an aqueous sodium hydroxide solution)introduced via a line 17, which causes the following two reactions tooccur. That is, while the second composition of chlorohydrins contactsthe alkaline agent, the pH of a mixture of the second composition ofchlorohydrins and the alkaline agent gradually increases as the contacttime elapses. Herein, when the pH of the mixture thereof is 7 or below,the catalyst of the second composition of chlorohydrins may react withthe alkaline agent to form an alkali metal salt. The formed alkali metalsalt may be precipitated and then removed in a second distillationdevice 200, which will be described below. On the other hand, when thepH of the mixture thereof is greater than 7, the chlorohydrins (e.g.,dichloropropanol) of the second composition of chlorohydrins may reactwith the alkaline agent to form epichlorohydrin. Herein, the inlinereactor 190 may be maintained at a temperature of 20 to 100° C. and at apressure of 1 to 2 atm. When the temperature and pressure of the inlinereactor 190 are within this range, the reaction may smoothly progress bythe application of an appropriate energy.

In addition, the first composition of chlorohydrins may include theabove-described catalyst, and accordingly, the second composition ofchlorohydrins may also include the catalyst. Consequently, the tworeactions may occur in the inline reactor 190: a reaction for formingepichlorohydrin, which is a main product; a reaction for forming analkali metal salt by contacting the catalyst with the alkaline agent.

As described above with reference to FIG. 1, the second composition ofchlorohydrins is formed by adding water to the first composition ofchlorohydrins (i.e., the composition introduced via the line 15) and thealkaline agent is added to the second composition of chlorohydrins;however, the present invention is not limited thereto. For example, thesecond composition of chlorohydrins may be prepared by directly addingan alkaline agent to the first composition of chlorohydrins to removethe catalyst and then adding water to the first composition ofchlorohydrins from which the catalyst is removed. That is, in FIG. 1,the locations of the lines 16 and 17 may be switched to each other.

A material including the epichlorohydrin and the alkali metal salt whichhas been discharged from the inline reactor 190 is introduced into thesecond distillation device 200 via a line 18.

The second distillation device 200 may be operated by distillationoperation based on a boiling point difference between constituents ofthe material including the epichlorohydrin and the alkali metal salt.

In addition, the second distillation device 200 may be maintained at anatmospheric pressure or lower, for example, 10 to 760 mmHg. When thepressure of the second distillation device 200 is within the rangedescribed above, epichlorohydrin may be separated with a highefficiency. The second distillation device 200 may include a vacuumdistillation column having a theoretical plate number of 2 to 50 (i.e.,a separation column 201). When the theoretical plate number of thevacuum distillation column is within this range, epichlorohydrin may beseparated with a high efficiency.

The effluent of the inline reactor 190 introduced into the seconddistillation device 200 via the line 18 is separated into a gas phasematerial and a liquid phase material in the separation column 201.Thereafter, the gas phase material is condensed in a second condenser203 and flows into a line 19 and then collected, and the liquid phasematerial is distilled in a second reboiler 202 and separated again intoa gas phase material and a liquid phase material. Afterwards, the gasphase material is recycled to the separation column 201 and the liquidphase material is discharged to the outside via a line 20. Inparticular, a material that is condensed in the second condenser 203 andflows into the line 19 after being discharged from an upper portion ofthe separation column 201 may include epichlorohydrin and water, and ahigh boiling point material that is discharged to the outside via theline 20 without evaporation in the reboiler 202 after being dischargedfrom a lower portion of the separation column 201 may include an alkalimetal salt. In this regard, the second reboiler 202 and the secondcondenser 203 may be maintained at a temperature of 60 to 110° C. and 0to 60° C., respectively.

In the second distillation device 200, epichlorohydrin may beadditionally generated.

These examples are for illustrative purposes only and are not intendedto limit the scope of the present invention.

EXAMPLE Preparation of Chlorohydrins and Epichlorohydrin from Glyceroland Hydrogen Chloride Gas in the Presence of an Acetic Acid Catalyst

By using the manufacturing process illustrated in FIG. 1, glycerol wasreacted with hydrogen chloride gas in the presence of an acetic acidcatalyst to prepare chlorohydrins and epichlorohydrin. Specificationsand operating conditions of devices used in the manufacturing processare shown in Table 1 below:

TABLE 1 Specifications of device Operating conditions First reactor CSTR120° C., 4 atm Two mixing vacuum ejector — devices Two decompression 46mmHg decompression valve devices Water removal vacuum distillationdehydration theoretical plate device column number: 20, pressure: 23mmHg reboiler 114° C., 46 mmHg condenser 49° C., 23 mmHg Second reactorCSTR 120° C., 4 atm First distillation vacuum distillation separationtheoretical plate device column number: 20, (rear end of pressure: waterremoval 23 mmHg device) reboiler 127° C., 46 mmHg condenser 56° C., 23mmHg Stripping device steam stripping stripping 152 mmHg device steam143° C., 3 atm Inline reactor tubular reactor  70° C., 1 atm Secondvacuum distillation separation theoretical plate distillation devicecolumn number: 20, (rear end of reboiler 104° C., 1 atm inline reactor)condenser 35° C., 1 atm

In addition, a total flow rate of materials transported via therespective lines in the manufacturing procedure, constituents of thematerials, and flow rates of the respective constituents wererespectively measured, and results thereof are shown in Table 2 below.Flow rates of the respective constituents were calculated as follows:the total flow rates of materials transported through the respectivelines were measured, component ratios of materials collected from therespective lines were analyzed by a gas chromatograph, and the totalflow rates was multiplied by component ratios of the materials.

TABLE 2 Line Total flow rate Components of Materials number (Kg/hr)transported Flow rate (Kg/hr) 1 315 glycerol 300 acetic acid 15 2 228HCl 228 3 5713 monochloropropanediol 555 dichloropropanol 3444 glycerolacetates 229 water 1083 glycerol 78 HCl 269 acetic acid 55 4 543monochloropropanediol 53 dichloropropanol 327 glycerol acetates 22 water103 glycerol 7 HCl 26 acetic acid 5 5 250 dichloropropanol 116 water 103HCl 26 acetic acid 5 6 293 monochloropropanediol 53 dichloropropanol 211glycerol acetates 22 glycerol 7 7 6382 monochloropropanediol 268dichloropropanol 5431 glycerol acetates 443 water 188 glycerol 6 HCl 468 21 HCl 21 9 314 monochloropropanediol 13 dichloropropanol 268 glycerolacetates 22 water 9 glycerol 0 HCl 2 10 254 dichloropropanol 243 water 9HCl 2 11 60 monochloropropanediol 13 dichloropropanol 25 glycerolacetates 22 glycerol 0 12 60 steam 60 13 85 monochloropropanediol 2dichloropropanol 24 water 59 14 35 monochloropropanediol 11dichloropropanol 1 glycerol acetates 22 water 1 glycerol 0 15 589monochloropropanediol 2 dichloropropanol 383 water 171 glycerol 0 HCl 28acetic acid 5 16 2000 water 2000 17 640 NaOH 160 water 480 18 3229dichloropropanol 8 epichlorohydrin 268 water 2718 glycerol 3 sodiumacetate 7 NaCl 215 NaOH 10 19 274 dichloropropanol 0 epichlorohydrin 272water 2 20 2955 water 2718 glycerol 4 sodium acetate 7 NaCl 219 NaOH 7

EVALUATION EXAMPLE

During reaction, samples were collected from the line 4 and the line 15at an interval of 5 minutes, and then, constituents of the samples andcontent ratios of the respective constituents were analyzed by a gaschromatograph. Analysis data obtained after reaching a steady state wasused to calculate a conversion rate of glycerol, a yield ofmonochloropropanediol, a yield of dichloropropanol, selectivity ofmonochloropropanediol, and selectivity of dichloropropanol, according toEquations 1 to 5. Results thereof are shown in Table 3 below.

TABLE 3 Sample collection site line 4 line 15 Glycerol conversion 97.5100 rate (%) Monochloropropanediol 14.6 0.6 yield (%) Dichloropropanolyield 77.9 94.2 (%) Chlorohydrins yield*¹ 92.5 94.8 (%)Monochloropropanediol 14.6 0.6 selectivity (%) Dichloropropanol 77.994.2 selectivity (%) Chlorohydrins 92.5 94.8 selectivity*² (%)*¹monochloropropanediol yield + dichloropropanol yield*²monochloropropanediol selectivity + dichloropropanol selectivity

Referring to Table 3, the sample collected from line 15 has a very highyield (94.8%) and a very high selectivity (94.8%). In addition, theyield and selectivity of dichloropropanol were much higher than theyield and selectivity of monochloropropanediol.

While the present invention has been particularly shown and describedwith reference to drawings and exemplary embodiments thereof, it will beunderstood by those of ordinary skill in the art that various changes inform and details may be made therein without departing from the spiritand scope of the present invention as defined by the following claims.

The invention claimed is:
 1. A method of preparing a chlorohydrincomposition in which a polyhydroxy aliphatic hydrocarbon is reacted witha chlorination agent in the presence of a catalyst, the method comprisesat least one combination of a series of unit operations comprising afirst reaction step for reacting the polyhydroxy aliphatic hydrocarbonwith the chlorination agent, a water removal step for separating areaction mixture comprising water as a by-product discharged from thefirst reaction step into a water-rich layer and a water-deficient layer,and a second reaction step for reacting at least one constituent of thereaction mixture from which water is removed, with at least one of thechlorination agent and an additional chlorination agent, wherein thesesteps are performed in this stated order, and the method furthercomprises purifying the reaction mixture discharged from the finalreaction step from among the plurarity of reaction steps to obtain achlorohydrin concentrate, and mixing the water-rich layer, and thechlorohydrin concentrate, wherein the catalyst comprises at least oneselected from the group consisting of an organic acid catalyst, acarboxylic acid-based catalyst, a nitrile-based catalyst, and a solidcatalyst, wherein the reaction mixture discharged from the firstreaction step, which is introduced into the water removal step,comprises the chlorination agent and water at a ratio of 10 to 25.0parts by weight of the total of the chlorination agent and theadditional chlorination agent and 75 to 90 parts by weight of water sothat the reaction mixture discharged from the first reaction step, whichis introduced into the water removal step, forms an azeotropic mixture.2. A method of preparing a chlorohydrin composition, the methodcomprising: introducing a polyhydroxy aliphatic hydrocarbon, a catalyst,and a chlorination agent into a first reactor in which the temperatureis maintained in a range of 50 to 200° C.; discharging a first reactoreffluent comprising water as a by-product from the first reactor;introducing at least a portion of the first reactor effluent into awater removal device to separate it into a water-rich layer and awater-deficient layer; introducing the water-deficient layer and anadditional chlorination agent into a second reactor in which thetemperature is maintained in a range of of 80 to 200° C.; introducing atleast a portion of a second reactor effluent into a purification devicefor chlorohydrins to obtain a chlorohydrins concentrate; and mixing thewater-rich layer and the chlorohydrin concentrate, wherein the catalystcomprises at least one selected from the group consisting of an organicacid catalyst, a carboxylic acid-based catalyst, a nitrile-basedcatalyst, and a solid catalyst, wherein the first reactor effluentintroduced into the water removal device comprises the chlorinationagent and water at a ratio of 10 to 25.0 parts by weight of the total ofthe chlorination agent and the additional chlorination agent and 75 to90 parts by weight of water so that the first reactor effluentintroduced into the water removal device forms an azeotropic mixture. 3.The method of claim 1, wherein the polyhydroxy aliphatic hydrocarbon isa C₂ to C₂₀ compound that has two or more hydroxyl groups bonded todifferent carbon atoms.
 4. The method of claim 3, wherein thepolyhydroxy aliphatic hydrocarbon is selected from the group consistingof 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol,3-chloro-1,2-propanediol, 2-chloro-1,3-propanediol, glycerol,1,2,4-butanetriol, 1,4-butanediol, esters of these compounds andmixtures thereof.
 5. The method of claim 1, wherein the chlorohydrinsincluded in the chlorohydrin concentrate is a compound having at leastone hydroxyl group and at least one chlorine atom that are bonded todifferent carbon atoms.
 6. The method of claim 5, wherein thechlorohydrins comprise at least one type of compound selected from thegroup consisting of 3-chloro-1,2-propanediol, 2-chloro-1,3-propanediol,1,3-dichloropropane-2-ol, and 2,3-dichloropropane-1-ol.
 7. The method ofclaim 2, wherein in the first reactor, a reaction product of thecatalyst and the polyhydroxy aliphatic hydrocarbon is formed as anintermediate product, and the intermediate product acts as a catalyst ina chlorination reaction of the polyhydroxy aliphatic hydrocarbon.
 8. Themethod of claim 7, wherein the polyhydroxy aliphatic hydrocarbon isglycerol, the catalyst is an acetic acid, and the intermediate productis glycerol acetate.
 9. The method of claim 1, wherein the chlorinationagent comprises a hydrogen chloride gas or an aqueous hydrochloric acidsolution.
 10. The method of claim 2, wherein the first reactor effluentintroduced into the water removal device is discharged when a conversionrate of the polyhydroxy aliphatic hydrocarbon is in a range of 30 to100% and the yield of the chlorohydrins is in a range of 30 to 95%, inthe first reactor.
 11. The method of claim 7, wherein the first reactoreffluent introduced into the water removal device comprises thepolyhydroxy aliphatic hydrocarbon, the chlorohydrins, and theintermediate product at a ratio of 0 to 90 parts by weight of thepolyhydroxy aliphatic hydrocarbon: 5 to 95 parts by weight of thechlorohydrins: 5 to 12 parts by weight of the intermediate product. 12.The method of claim 2, wherein a chlorination agent is additionallyintroduced into the second reactor.
 13. The method of claim 2, wherein aretention time of the reactor contents in the first reactor is in arange of 20 minutes to 1 hour, and a retention time of the reactorcontents in the second reactor is in a range of 1 to 3 hours.
 14. Themethod of claim 2, wherein the water removal device is operated bydistillation operation using a boiling point difference betweenconstituents of the first reactor effluent.
 15. The method of claim 2,wherein the first reactor and the second reactor are maintained at anatmospheric pressure or higher, and the water removal device ismaintained at an atmospheric pressure or lower.
 16. The method of claim15, wherein the first reactor and the second reactor are maintained at 1to 20 atm, and the water removal device is maintained at 10 to 760 mmHg.17. The method of claim 16, wherein the water removal device comprises avacuum distillation column having a theoretical plate number of 2 to 50.18. The method of claim 15, wherein the first reactor effluent isintroduced into the water removal device after being decompressed in adecompression device.
 19. The method of claim 18, wherein thedecompression device comprises a decompression valve.
 20. The method ofclaim 2, wherein the first reactor and the second reactor are eachindependently a continuous stirred-tank reactor, a batch reactor, asemi-batch reactor, or a plug flow reactor.
 21. The method of claim 2,wherein the second reactor effluent comprises 0 to 10 parts by weight ofthe polyhydroxy aliphatic hydrocarbon, 80 to 98 parts by weight of thechlorohydrins, 0 to 10 parts by weight of the total of the chlorinationagent and the additional chlorination agent, and 1 to 20 parts by weightof water.
 22. The method of claim 1, wherein the chlorohydrincomposition comprises 0 to 10 parts by weight of the polyhydroxyaliphatic hydrocarbon, 60 to 96 parts by weight of the chlorohydrins, 0to 20 parts by weight of the total of the chlorination agent and theadditional chlorination agent, and 0 to 30 parts by weight of water. 23.The method of claim 2, wherein the polyhydroxy aliphatic hydrocarbon isa C₂ to C₂₀ compound that contains two or more hydroxyl groups bonded todifferent carbon atoms.
 24. The method of claim 23, wherein thepolyhydroxy aliphatic hydrocarbon is selected from the group consistingof 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol,3-chloro-1,2-propanediol, 2-chloro-1,3-propanediol,glycerol,1,2,4-butanetriol, 1,4-butanediol, esters of these compoundsand mixtures thereof.
 25. The method of claim 2, wherein thechlorohydrins included in the chlorohydrin concentrate is a compoundhaving at least one hydroxyl group and at least one chlorine atom thatare bonded to different carbon atoms.
 26. The method of claim 25,wherein the chlorohydrins comprise at least one type of compoundselected from the group consisting of 3-chloro-1,2-propanediol,2-chloro-1,3-propanediol, 1,3-dichloropropane-2-ol, and2,3-dichloropropane-1-ol.
 27. The method of claim 2, wherein thecatalyst comprises at least one selected from the group consisting of anorganic acid catalyst, a carboxylic acid-based catalyst, a nitrile-basedcatalyst, and a solid catalyst.
 28. The method of claim 2, wherein thechlorination agent comprises a hydrogen chloride gas or an aqueoushydrochloric acid solution.
 29. The method of claim 2, wherein thechlorohydrin composition comprises 0 to 10 parts by weight of thepolyhydroxy aliphatic hydrocarbon, 60 to 96 parts by weight of thechlorohydrins, 0 to 20 parts by weight of the total of the chlorinationagent and the additional chlorination agent, and 0 to 30 parts by weightof water.